Vehicle drivelines typically include constant velocity joints, side shafts and propeller shafts in various configurations to provide motive power for the vehicle. Constant velocity fixed joints are known in various designs. Such joints are used primarily in the driveline of a motor vehicle for driving the wheels of a motor vehicle. They can be used in either propeller shafts or in side shafts. Side shafts extend from the axle drive to the driven wheels; for example, they connect the output ends of the rear axle differential with the driven wheel hubs of the wheels. Propeller shafts serve to transmit the drive from the gearbox output of the front wheel drive unit to the rear axle differential associated with the rear axle.
As far as propeller shafts are concerned, a number of different designs are used. They may comprise, for example, a shaft with two joints which are arranged at the ends of the shaft which serve to be connected to the gearbox output in front, and to the drive input at the rear. Multi-section propeller shafts are also common. For example, two propeller shaft portions can be connected by a center bearing or intermediate bearing. Normally, at the ends of the propeller shafts, i.e., towards the gearbox output and the drive input, there are arranged universal joints. It is also possible for a universal joint to be provided in the central region. A constant velocity plunging joint can also be provided in the central region. The propeller shafts themselves typically are made of metal, although carbon fiber and other materials have also been used.
The drive unit of the motor vehicle generates vibrations which, in prior art assemblies, are transmitted to the propeller shaft in the form of movement vibrations and structure-borne sound. Moreover, vibrations are induced from the relatively high rotational speeds of the propeller shafts themselves. In addition, changing torque values and rotational speeds constantly occur during the transmission of the rotational movement throughout the driveline assembly. Load values suddenly increasing to 10 times the nominal torque, and rotational speeds up to 10,000 revolutions per minute are not rare.
To reduce the transmission of vibration and structure-borne sound to the vehicle compartment, multi-sectional propeller shafts are typically used with an intermediate or center bearing located at a nodal point along the propeller shaft assembly. Dynamic dampers are also used along an intermediate portion of multi-sectional propeller shafts to minimize vibrations. In some cases, it would be preferable for packaging concerns, or cost/weight concerns to employ a smaller diameter propeller shaft. There also exists a need for a more rigid propeller shaft to permit longer shafts without the need for an intermediate bearing or dynamic damper.